1. Technical Field
The present invention relates, in general, to a method and system for providing a multiview three-dimensional image of an object and, in particular, to a method and system for providing a multiview three-dimensional image of an object by using a moving aperture realized with a scanner.
2. Description of Related Art
Several methods have conventionally been used for capturing two-dimensional perspective images of a three-dimensional object from a plurality of viewing directions in order to provide a multiview three-dimensional image of the object. These methods involve: (1) using a plurality of synchronized cameras, where each camera captures two-dimensional images from a different one of the plurality of viewing directions; (2) using a single camera moved in succession to each of the plurality of viewing directions, where the camera captures two-dimensional images from each of the plurality of viewing directions; or (3) using a single stationary camera having a wide aperture objective lens and spatially modulating the light transmitted by the lens with a plurality of elecrtro-optical shutters, where each of the shutters corresponds to a different one of the plurality of viewing directions.
In the first method, multiple synchronized cameras capture two-dimensional images of the object at 30 frames per second and send the captured images to a receiving device. The receiving device superposes the two-dimensional images and transmits the superposed images to a display device. A special optical plate, such as a lenticular screen, a parallax barrier, or a holographic screen, is needed to display the superposed images.
In the second method, a single camera must be moved to each of the plurality of viewing directions. However, it is difficult to move a camera between adjacent viewing directions quickly enough to enable the camera to capture 30 images per second of an object, especially a moving object, from each of the plurality of viewing directions.
In the third method, multiple electro-optical shutters, such as liquid crystal shutters, are arranged at the principal plane of a camera's wide-aperture objective. By sequentially opening and closing successive shutters, two-dimensional images of an object are captured from each of the plurality of viewing directions. Although this method requires only a single stationary camera to obtain multiview images comparable to those obtained with multiple synchronized stationary cameras, considerable light is lost at the shutters. For example, when liquid crystal shutters are used, more than 3/4 of the incident light is attenuated by polarizers attached to the shutters, so that the brightness of the images is greatly reduced. Moreover, since the camera must have a large aperture objective, the two-dimensional image sensor must have a correspondingly large sensitive area. In addition, since each shutter must open and close 30 times per second to capture 30 images per second from each viewing direction, high speed shutters are required.